This invention relates to the use of certain phenylene dioxamic acids in treating allergic ocular responses, such as hayfever, conjunctivitis, atopic and keratoconjunctivitis, vernal conjunctivitis, giant capillary conjunctivitis, and other diseases where mast cell degranulation are important in the etiology, by topical administration of said active to the affected eye; also disclosed are pharmaceutical compositions comprising said actives.
Such phenylene dioxamic acids are generically and specifically disclosed, to a representative extent, in U.S. Pat. No. 3,993,679 (issued Nov. 23, 1976), which patent is fully incorporated herein by reference to the extent of defining the subject phenylene dioxamic acids and their synthesis. A species of the defined phenylene dioxamic acid genus of particular interest and of representative value is N-N'-(2-chloro-5-cyano-m-phenylene) dioxamic acid and its pharmaceutically acceptable salts and esters, such as, di-[tris(hydroxymethyl)methylammonium]-N-N'(2-chloro-5-cyano-m-phenylene)d ioxamate: ##STR1##
The phenylene dioxamic acid of Structure I, above, is known also by the name lodoxamide tromethamine.
The phenylene dioxamic acids of incorporated U.S. Pat. No. 3,993,679 are known to be useful as antiallergics, and, according to the patent disclosure, may be delivered by oral, parenteral, inhalation, rectal means, or by eye drops. The specific salt form of Structure I, above, is disclosed in U.S. Pat. No. 4,524,063 (issued Jun. 18, 1985) to be useful as a topical, ophthalmic antiallergic. However, the patent teaches that to be clinically efficacious the specific lodoxamide salt must be used in a concentration range of from 1-10%, preferably at a level of 5%, in an aqueous vehicle comprising 1-5% polyvinyl alcohol. Such dosage levels are considered quite high--particularly since lodoxamide tromethamine has been reported to cause several types of side effects in a dose related manner. For example, on systemic administration via the oral, intravenous, intrabronchial, or intranasal routes a generalized warming sensation has been reported. Less frequently reported side effects include headaches, nausea, vomiting, nervousness, and the like. The severity and intensity of the side effects decreased with continued usage. The report of such systemic side effects after topical application of an ophthalmic preparation comprising lodoxamide tromethamine has al so been reported and is disturbing to the patients and clinicians. Consequently, the therapeutic method and compositions disclosed in the above-cited U.S. Pat. No. 4,524,063 have not been accepted.
Unexpectedly it has been discovered that the phenylene dioxamic acids genus defined by U.S. Pat. No. 3,993,679, which specifically includes lodoxamide and its pharmaceutically acceptable salts and esters including the salt of Structure I, are efficacious for the antiallergic indication when the phenylene dioxamic acid actives are delivered topically by conventional eye drop to the eye at dosage levels under 0.5% concentration when formulated with vehicles of the present invention. In fact, the preferred liquid dosage form for conventional eye drop delivery of the present invention comprises the phenylene dioxamic acid active in the range of 0.1 to 0.25 weight percent. Use of the resulting compositions substantially eliminates occurrence of the aforementioned side effects, and the level of efficacy, quite unlike the teachings of the cited U.S. Pat. No. 4,524,063, is high and acceptable by the ophthalmic clinical community.